Just the character to kit out key servicemen (6)
I believe the answer is:
kermit
'just the character' is the definition.
I can't judge whether this definition defines the answer.
'kit out key servicemen' is the wordplay.
'out' means one lot of letters goes inside another.
'key servicemen' becomes 'erm' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'kit' going around 'erm' is 'KERMIT'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for kermit that I've seen before include "Famous TV frog" , "Croaking muppet?" , "Muppet frog" .)